The 901 Series had ample scope for development, though perhaps only the Porsche organization could see it. The first major advance came in late 1966, and it was an exciting one: the hot 911S — "S" for Super. With this, Porsche returned to its old three-tier lineup of Norma, Super, and Carrera, respectively represented by the 912, standard 911, and the new S.
The S boasted modifications typical of a higher-performance Porsche: reprofiled cam, larger valves, better porting, loftier compression (9.8:1 vs. 9.0), larger jets for the Weber carbs (which were otherwise much like those given to the base 911 from early '66).
The result was 30 more horsepower for a total 160 DIN horsepower European (180 SAE). Torque improved fractionally, to 127 pound-feet, but peaked fully 1,000 rpm higher.
Unlike other models, the S lacked a choke, but pumping the accelerator was usually enough for starting. On the other hand, merely blipping the throttle on the freer-breathing S would send the tach needle zinging to its 7,300-rpm redline. Porsche thus wisely fitted an ignition cutout that interrupted spark to the plugs near maximum revs, thus protecting the valvetrain from overly enthusiastic drivers.
Naturally, the S also received chassis upgrades to match its extra power. These included a rear anti-roll bar (augmenting the one in front), Koni shocks, ventilated instead of solid-rotor disc brakes all-round and — soon to be a 911 hallmark — pretty, five-spoke Fuchs alloy wheels that cut five pounds from unsprung weight at each hub. Curiously, the S had the same skinny tires as the normal Porsche 911, at least for the moment.
S gear ratios were evenly spaced except for the five-speed transmission's overdrive top, which was purposely very "high." It gave 100 mph at 4,200 rpm, hardly a strain for the free-revving flat-six. Pulling max rpm in the lower gears netted 0-60 in eight seconds or less and ran a standing quarter-mile of under 16 seconds at 90-plus mph.
Interestingly, the torque curve had two distinct steps. As Autocar reported: "The catalogue peak comes at 5200 rpm, but before that, at about 3000, the engine takes a deep breath and literally surges up to the next step, where the extra punch feels like an additional pair of cylinders being switched in. This kick in the back leaves passengers unaccustomed to it slightly winded, and it is sudden enough to cause momentary wheelspin on wet surfaces, even in third."
As for road manners, the S earned mixed reviews. "Oversteer is back — and Porsche's got it!" screamed Car and Driver. "At low lateral accelerations it understeers mildly . . . By 0.70 g, it's in a full-blooded four-wheel drift. . . . Beyond the limit of . . . adhesion, the 911S reacts like any car with a rearward weight bias, and spins, or, if you're quick enough to catch it, power-slides like an old dirt-track roadster."
Road & Track found "less of the [low-speed] understeer that so surprised us in the 911, [though above 40 mph] we were hard-pressed to detect any difference. . . . Certainly it's easier to hang out the tail if you're in the right gear, simply because of the increased power. But the simple application of steering to the 911S at highway speeds gets the same results as in the 911, which means stick-stick-stick-oversteer! And you'd better know what you're doing in that last phase."
In a calmer vein, C/D declared that "Porsche's admonition, 'not for the novice,' is a bit gratuitous. Within normal driving limits and with reasonable caution, the 911S handles predictably, controllably, and head and shoulders above anything else on the road."
As proof, the magazine reported lateral acceleration of 0.93 g in right turns, 0.89 g in lefts, and a calculated 0.81 g overall. These figures, good even today, came despite the modest rubber.
Both U.S. magazines were disappointed in Porsche 911S braking, blaming the skinny tires for unchanged stopping distances despite the model's new vented rotors. C/D also found some minor lapses in workmanship, though its test car was admittedly "right off the boat" and had not been dealer-prepped.
The engines in both test cars evidently weren't up to scratch either. Though C/D cut a full second off Porsche's claimed 7.5-second 0-60 time, R&T managed only 8.1. But there was no disputing that the engine itself was beautifully smooth and fantastically willing.
Autocar applauded "the superb lightness of all the controls" and "excellent seating . . . The Porsche 911S is a car one never likes to leave parked when one could be driving it."
Road & Track was more critical, saying that in American conditions the Porsche 911S "offers no real gain over the 911 and perhaps even a slight loss. It is a bit less flexible at ordinary speeds; deceleration below about 1800 rpm brings on bucking and considerable clatter from the drivetrain, demanding an immediate downshift." But even R&T's hard-nosed editors weren't immune to that intoxicating powerplant: "For the driver who really wants to get on with it, the 911S is bound to be more fun than the 911."
The fun suddenly stopped when the Porsche 911S left the American market for 1968 (though it continued in Europe). While the ostensible reason was that year's new federal emission standards and the engine retuning needed to meet them, some say it was the persistent plug-fouling, which had become a tremendous service problem. But the S would return, for 1969.